Lifting-jack



(No Model.) 2 Sheets--Sheet l. Y

J. W. HAWKINS.

- LIFTING JACK. 7 No. 361,944. Patented Apr. 26, 1887.

. mm mm (No Model.) 2 Sheets- 8mm; 2.

J; W. HAWKINS.

LIFTING JACK.

No. 361,944. Patented Apr. 26, 1887.

v lifting-pawls.

UNITED STATES PATENT OFFICE.

J. IVESLEY HAWKINS, OF KENT, OHIO.

LlFTlNG-JACK.

SPECIFICATION forming part of Letters Patent No. 361.944, dated April26, 1887.

Application filed February 2, 1887. Serial No. 226,262. (No model.)

To all whom it may concern;-

Be it known that I, J. WEsLEY HAWKINS, of Kent, in the county of Portageand State of Ohio, have invented certain new and useful Improvements inLifting-Jacks; and Ido hereby declare the following to be a full, clear,and exact description of the invention, such as will enable othersskilled in the art to which it pertains to make and use the same.

My invention relates to improvements in lifting-jacks; and it consistsin certain features of construction and in combination of parts,hereinafter described, and pointed out in the claims.

This invention is designed as an improvement on a lifting-jack patentedJune 8, 1886, to J. Wesley Hawkins, No. 343,312.

In the accompanying drawings, Figures 1 and 2 are respectively a sideand front eleva tion of a lifting-jack embodying my invention. Fig. 3 isan elevation in section, and Fig. 4 a plan of the retaining-pawls andconnected mechanism. Figs. 5 and 6 are respectively a side and endelevation of the yoke for the Figs. 7 and 8 are plans, respectively, ofthe lifting and releasing levers.

A represents the standard, that is usually of cast-iron, with a broadbase, A. The lower or main portion of the standard has avertical recess,A, in which operates the lifting-bar B. This bar has a head, I), forlifting weights that are sufficiently elevated, and a toe, b, thatextends outside of the recess A, for lifting loads that are lowerdown-such, for instance, as rails of a railroad-track-by reason of whichthis device is well adapted for a track-jack. The bar B slides throughsleeves a and a, connected with the standard, these sleeves formingguides for the lifting-bar. A forked lifting-lever, C, is pivoted at cto the standard. The outer end, 0, of the lever has a conical socket forreceiving a wooden extension-lever. (Not shown.) To the extreme ends ofthe prongs c are pivoted hooks D, the latter engaging bails E of theyoke E. This yoke is rectangular in plan, with the end pieces, 6,

rounded to form fulcrums for the pawls F.

These pawls engage, respectively, gibs G, that clamp the lifting-bar.Each gib has lugs g located below theyoke, which prevent the gibs frombeing lifted out of place.

Each gib on the back side has a tooth similar to the tooth g of gibs J,that engages a corresponding notch, f, in the engaging pawl and retainsthe gib and pawl in the proper relative posit-ion, causing them to movetogether. The face f of each pawl is slightly eccentric with the axis ofthe pawl, by reason of which, when the yoke is elevated by thehoisting-lever, the gravity of the gibs and pawls causing them todescend, the gibs are made to clamp the liftingbar and elevate it, thepawls acting as a toggle-j oint to press the gibs against thelifting-bar.

The retaining mechanism, consisting of the yoke H, pawls I, and gibs J,is the same as just described, except that the yoke H has no bails forlifting it; but in place thereof the yoke H rests on shoulders a of thestandard. A forked releasing'lever, K, is pivoted to the standard at k.The prongs of this lever extend through suitable slots made inthestandard and reach under the gibs J. When the lifting-bar B has beenelevated, and it is-desired to depress the same, the outer end of thelever O is elevated, and the yoke E is thereby depressed until the lowerends of the gibs G rest upon the sleeve a, by means of which the gibs Gand pawls F are slightly elevated and the gibs are caused to releasetheir grip on the lifting-bar. While the parts are in this position, bypressing down on the outer end of the lever K, the prongs thereof aremade to lift the gibs J, when the lifting-bar will descend by gravity.

With mechanism as described in the patent aforesaid the pawls come indirect contact with the lifting-bar, and as the contact-surfaces arenecessarily limited there is a tendency to abrade the surface of thelifting-bar and even indent the latter when the load is excessive. Withmy improved device, owing to the large surface of the gibs that engagethe lifting-bar, this difficulty is entirely overcome, the result beingthat the wear of these parts is merely nominal. The gibs and pawls beingshort and strong, the engaging surfaces of each may be hardened withoutdanger of breakage, and the wear ofthese parts is therefore reduced to aminimum.

What I claim is- 1. In a lifting-jack, the combination,with a standard,a lever pivoted thereto, a liftingbar, and a yoke arranged astride theliftingbar, of gibs and pawls arranged in pairs and supported by theyoke, said gibs being made 5 to clamp the lifting-bar, the pawls beingfulcrumed on the yoke and made to serve as toggle-joints in pressing thegibs against the lifting-bar, substantially as set forth.

2. In a lifting-jack, the combination of the x0 lifting-bar, yoke,pawls, and gibs having lugs extending under the yoke for engaging thelatter, said lugs serving as stops to prevent the gibs from upwarddisplacement, substantialiy as set forth.

J. WESLEY HAWKINS.

\Vitnesses:

C. R. SAUNDERS, J. B. MILLER.

